In a technical field of wireless communication, a signal received wirelessly may be stored and used in reproduction processing at a later date. Since a large storage capacity is needed as a storage period becomes longer in this case, it is useful to compress and store the received signal.
As a technique for compressing and storing the signal received wirelessly, a Patent Document 1 is well known. The Patent Document 1 describes that a time-frequency transform of the received signal is performed on a wireless received signal to make a determination as to whether it is a non-signal, on the basis of the spectral amplitude value of a frequency spectrum, and the signal whose band has been determined to be the non-signal is compressed.